Communication networks are becoming increasingly popular with the increase in the need for communication and information exchange. A typical communication network includes numerous base stations and subscriber stations. These subscriber stations exchange information with each other via base stations. The subscriber stations exchange data with a base station in a series of frames. Each frame includes, for example, an uplink data frame of data and a downlink data frame of data. The uplink data frame can be defined as a sub-frame, during which the subscriber stations send data to the base station. The downlink data frame can be defined as a sub-frame, during which the base station sends data to the subscriber stations. A typical base station communicates with the subscriber stations by allocating respective data slots to different subscriber stations. These data slots are allocated in the downlink data frame as well as in the uplink data frame.
Generally, base stations and subscriber stations comply with the Institute of Electrical and Electronics Engineers (IEEE) standards 802.16-2004 and/or 802.16-2005. According to section 8.4.4.2 of the IEEE standard 802.16-2004, a Transmit/receive Transition Gap (TTG) and a Receive/transmit Transition Gap (RTG) needs to be inserted between the downlink data frame and uplink data frame, and also at the end of each frame. According to these standards, a base station should not transmit information to a subscriber station later than (Subscriber Station Receive/Transmit Turnaround Gap+Round Trip Delay) before the beginning of the first scheduled uplink allocation in any uplink data frame. Further, the base station should not transmit downlink information to the subscriber station earlier than (Subscriber Station Transmit/Receive Turnaround Gap-RTD) after the end of the allocation in the last uplink data frame.
According to the specifications of the IEEE standards 802.16-2004 and 802.16-2005, TTG is equal to the sum of SSRTG (Subscriber Station Receive/Transmit Turnaround Gap) and RTD (Round Trip Delay). SSRTG and SSTTG (Subscriber Station Transmit/receive Transition Gap) are parameters provided by the subscriber station to the base station when the subscriber station enters the communication network. TTG is a pre-configured value set that corresponds to the base station. The RTD component is a major portion of the TTG. The RTD cannot be changed once the SSRTG has been reported to a base station by a subscriber station. Therefore, bandwidth may be wasted by subscriber stations that are close to the base station, as well as by subscriber stations that are moving closer to the base station, resulting in a decrease in data throughput for the corresponding communication network.